1. Field of the Invention
The present invention relates generally to solar cells, and more particularly but not exclusively to methods and structures for interconnecting solar cells in a solar cell module.
2. Description of the Background Art
Solar cells, also referred to as “photovoltaic cells,” are well known devices for converting solar radiation to electrical energy. They may be fabricated on a semiconductor wafer using semiconductor processing technology. Generally speaking, a solar cell may be fabricated by forming p-doped and n-doped regions in a silicon substrate. Solar radiation impinging on the solar cell creates electrons and holes that migrate to the p-doped and n-doped regions, thereby creating voltage differentials between the doped regions. In a backside-contact solar cell, the doped regions are coupled to conductive leads on the backside of the solar cell to allow an external electrical circuit to be coupled to and be powered by the solar cell. Backside-contact solar cells are disclosed in U.S. Pat. Nos. 5,053,083 and 4,927,770, which are both incorporated herein by reference in their entirety.
Several solar cells may be connected together to form a solar cell array. In a solar cell array, a conductive area coupled to a p-doped region (hereinafter “positive area”) of one solar cell is connected to a conductive area coupled to an n-doped region (hereinafter “negative area”) of an adjacent solar cell. The positive area of the adjacent solar cell is then connected to a negative area of a next adjacent solar cell and so on. This chaining of solar cells may be repeated to connect several solar cells in series to increase the output voltage of the solar cell array. Backside-contact solar cells have been connected together using a relatively long, single strip of perforated conductive material. U.S. Pat. No. 6,313,395, which is incorporated herein by reference in its entirety, also discloses the interconnection of several backside-contact solar cells to form a solar cell array.
Attempts have been made to visually shield front-side electrical connections of traditional (i.e., front side contact) solar cells. For example, Webasto Roof Systems, Inc. has introduced a traditional solar cell array with bus bars that are covered with paint or tape to make the solar cell array visually appealing for use in the roofs of automobiles. Electrical connections to a traditional solar cell are made to contact portions on the front side (i.e., the side facing the sun) of the solar cell. Because backside-contact solar cells have all the electrical connections on the backside, conventional approaches to shielding electrical connections in traditional solar cells are not readily applicable to backside-contact solar cells.